The prior art is replete with software enabling a first user to establish a telephone-like conversation with a second user running the same software via a packet network, such as, for example, the Internet.
These softwares usually run on personal computers equipped with microphones to capture the sounds and with sound cards to reproduce the sounds from the other user. The software therefore captures the sound from a first user, digitises it, compresses it, and forwards it to the Packet Network address (Internet Protocol address or IP address) of the second user. The sounds is then uncompressed, transferred back to analog sound by the sound card and reproduced on the premises of the second user. Of course, these steps are performed bidirectionally to result in a full duplex connection.
The drawbacks of the above mentioned software system are multiple. For example, a dedicated PC must be used as a telephone, both users must be similarly equipped and running the same software and it is not possible to reach users equipped with conventional telephones.